Remote Limb Ischaemic Postconditioning Protects Against Myocardial Ischaemia/Reperfusion Injury in Mice: Activation of JAK/STAT3-Mediated Nrf2-Antioxidant Signalling

• Main Authors: Sumin Gao, Leyun Zhan, Zhengchao Yang, Ruili Shi, Haobo Li, Zhengyuan Xia, Shiying Yuan, Qing-ping Wu, Tingting Wang, Shanglong Yao
• Format: Article
• Language: English
• Published: Cell Physiol Biochem Press GmbH & Co KG 2017-10-01
• Series: Cellular Physiology and Biochemistry
• Subjects: Remote limb ischaemic postconditioning; JAK/STAT3; Akt; ENOS; Nrf2; HO-1
• Online Access: https://www.karger.com/Article/FullText/481755

Background: This study aimed to evaluate the protective effect and mechanisms of remote limb ischaemic postconditioning (RIPostC) against myocardial ischaemia/reperfusion (IR) injury. Methods: Male mice underwent 45 min of coronary artery occlusion followed by 2 h of reperfusion. RIPostC was achieved by three cycles of 5 min of ischaemia and 5 min of reperfusion in the left hind limb at the start of the reperfusion period. After 2 h of cardiac reperfusion, myocardial infarct size, cardiac enzyme release, apoptosis and oxidative stress were assessed. Protein expression and phosphorylation were measured by Western blotting. Results: RIPostC significantly decreased cardiac IR injury, as reflected by reduced infarct size and cellular apoptosis (22.9 ± 3.3% vs 40.9 ± 6.2% and 13.4% ± 3.1% vs 26.2% ± 3.1%, respectively, both P < 0.01) as well as plasma creatine kinase-MB (CK-MB) and lactate dehydrogenase (LDH) release (21.97 ± 4.08 vs 35.86 ± 2.91 ng/ml and 6.17 ± 0.58 vs 8.37 ± 0.89 U/ml, respectively, both P < 0.01) compared with the IR group. RIPostC significantly increased the phosphorylation of myocardial STAT3, Akt and eNOS (P < 0.01). In addition, RIPostC elevated the nuclear translocation of Nrf2 and the expression of HO-1 and reduced myocardial oxidative stress (P < 0.05). Interestingly, pretreatment with the JAK/STAT3 inhibitor AG490 blocked the cardioprotective effect of RIPostC accompanied by decreased phosphorylation of myocardial STAT3, Akt and eNOS (P < 0.05), decreased nuclear translocation of Nrf2 and expression of HO-1, as well as increased oxidative stress (P < 0.05). Conclusion: RIPostC attenuates apoptosis and protects against myocardial IR injury, possibly through the activation of JAK/STAT3-mediated Nrf2-antioxidant signalling.